diff --git a/src/main/java/com/eactive/apim/portal/apps/apiservice/service/ApiSpecService.java b/src/main/java/com/eactive/apim/portal/apps/apiservice/service/ApiSpecService.java
index 3536942..f96db0a 100644
--- a/src/main/java/com/eactive/apim/portal/apps/apiservice/service/ApiSpecService.java
+++ b/src/main/java/com/eactive/apim/portal/apps/apiservice/service/ApiSpecService.java
@@ -36,6 +36,7 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.commons.collections4.CollectionUtils;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.lang3.Strings;
 import org.springframework.stereotype.Service;
 
 @Service
@@ -155,10 +156,10 @@ public class ApiSpecService {
             updateReferences(pathItem, apiId);
 
             String tmpFullPath = StringUtils.isNotEmpty(basePath)
-                ? StringUtils.join(basePath, "/", StringUtils.removeStart(path, "/"))
+                ? StringUtils.join(basePath, "/", Strings.CS.removeStart(path, "/"))
                 : path;
 
-            final String fullPath = StringUtils.replacePattern(tmpFullPath, "//+", "/");
+            final String fullPath = tmpFullPath.replaceAll("//+", "/");
 
             // HTTP 메소드별로 중복 체크
             pathItem.readOperationsMap().forEach((httpMethod, operation) -> {
@@ -294,7 +295,7 @@ public class ApiSpecService {
             return StringUtils.EMPTY;
         }
         Server server = api.getServers().get(0);
-        return StringUtils.removeEnd(server.getUrl(), "/");
+        return Strings.CS.removeEnd(server.getUrl(), "/");
     }
 
     private void mergeComponents(OpenAPI currentAPI, String apiId, String apiName, Map<String, Object> mergedComponents, ObjectMapper objectMapper) {
diff --git a/src/main/java/com/eactive/apim/portal/common/validator/CellPhoneValidator.java b/src/main/java/com/eactive/apim/portal/common/validator/CellPhoneValidator.java
index 86cc89c..3cbc272 100644
--- a/src/main/java/com/eactive/apim/portal/common/validator/CellPhoneValidator.java
+++ b/src/main/java/com/eactive/apim/portal/common/validator/CellPhoneValidator.java
@@ -1,6 +1,7 @@
 package com.eactive.apim.portal.common.validator;
 
 import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.lang3.Strings;
 import org.springframework.stereotype.Component;
 
 import javax.validation.ConstraintValidator;
@@ -39,14 +40,8 @@ public class CellPhoneValidator implements ConstraintValidator<CellPhone, String
         }
 
         // 기존의 prefix 체크 로직 유지
-        return StringUtils.startsWith(cellPhone, "+821") ||
-                StringUtils.startsWith(cellPhone, "821") ||
-                StringUtils.startsWith(cellPhone, "010") ||
-                StringUtils.startsWith(cellPhone, "011") ||
-                StringUtils.startsWith(cellPhone, "016") ||
-                StringUtils.startsWith(cellPhone, "017") ||
-                StringUtils.startsWith(cellPhone, "018") ||
-                StringUtils.startsWith(cellPhone, "019");
+        return Strings.CS.startsWithAny(cellPhone,
+                "+821", "821", "010", "011", "016", "017", "018", "019");
     }
 
     private boolean isValidPartLength(String prefix, String middle, String last) {
diff --git a/src/test/java/com/eactive/apim/portal/common/compatibility/CommonsLangUpgradeCompatibilityTest.java b/src/test/java/com/eactive/apim/portal/common/compatibility/CommonsLangUpgradeCompatibilityTest.java
index 1aa69fb..f8d3361 100644
--- a/src/test/java/com/eactive/apim/portal/common/compatibility/CommonsLangUpgradeCompatibilityTest.java
+++ b/src/test/java/com/eactive/apim/portal/common/compatibility/CommonsLangUpgradeCompatibilityTest.java
@@ -11,6 +11,7 @@ import com.eactive.apim.portal.common.util.UserTypeUtil;
 import com.eactive.apim.portal.common.validator.CellPhoneValidator;
 import org.apache.commons.lang3.StringEscapeUtils;
 import org.apache.commons.lang3.StringUtils;
+import org.apache.commons.lang3.Strings;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.DisplayName;
 import org.junit.jupiter.api.Test;
@@ -46,21 +47,21 @@ class CommonsLangUpgradeCompatibilityTest {
                 () -> assertEquals("", StringUtils.trimToEmpty(null)),
                 () -> assertEquals("api-001", StringUtils.defaultIfBlank(" ", "api-001")),
                 () -> assertEquals("API 이름", StringUtils.defaultIfBlank("API 이름", "api-001")),
-                () -> assertTrue(StringUtils.equalsAnyIgnoreCase(" Y ".trim(), "true", "y", "1"))
+                () -> assertTrue(Strings.CI.equalsAny(" Y ".trim(), "true", "y", "1"))
         );
     }
 
     @Test
     @DisplayName("API 경로와 메시지 리소스명 문자열 처리가 유지된다")
     void keepsPathAndResourceNameBehavior() {
-        String fullPath = StringUtils.join("/openapi/", "/", StringUtils.removeStart("/users", "/"));
-        String normalizedPath = StringUtils.replacePattern(fullPath, "//+", "/");
+        String fullPath = StringUtils.join("/openapi/", "/", Strings.CS.removeStart("/users", "/"));
+        String normalizedPath = fullPath.replaceAll("//+", "/");
         String resource = "/WEB-INF/messages/messages_ko.properties";
         String baseName = StringUtils.substringBeforeLast(resource, ".properties");
 
         assertAll(
                 () -> assertEquals("/openapi/users", normalizedPath),
-                () -> assertEquals("/openapi", StringUtils.removeEnd("/openapi/", "/")),
+                () -> assertEquals("/openapi", Strings.CS.removeEnd("/openapi/", "/")),
                 () -> assertEquals("/WEB-INF/messages", StringUtils.substringBeforeLast(baseName, "/")),
                 () -> assertEquals("messages_ko", StringUtils.substringAfterLast(baseName, "/")),
                 () -> assertEquals("messages", StringUtils.substringBeforeLast("messages_ko", "_"))